| Objective: In this experimental study,the sealing effect of three kinds of composite resin materials with different thicknesses of screw-retained prosthetic screw access holes was evaluated by setting different types and thicknesses of filling groups,which provided a reliable theoretical basis for filling resin and filling thickness in clinical practice.Materials and Methods: A soft tissue horizontal implant substitute was implanted in the left maxillary first molar site of the standard plaster model to prepare a planting impression and to cast a plaster model.The CAD software was used to design the restoration,and 45 screw-retained zirconia ceramic crowns of uniform size were produced.They are connected to the substitute body with a torque of 35N·cm,fill the cotton ball at the bottom of the screw hole and compact it.The filling thickness of 1mm,2mm and 3mm is reserved at the top.Each thickness is filled with Z350 general-purpose resin,Z350 flow-type resin,and Ceramage polymerized ceramic resin.All test pieces are divided into 9 groups according to the type of resin and filling thickness,and each group is 5;then put the test pieces into the thermal cycle and perform 1200 cycles of hot and cold cycle in a water bath at 5?and 55?,and then immersed in a 0.5% basic fuchsin solution,and the test piece was vertically loaded 16,000 times using an electronic universal testing machine.After loading,remove the filling resin in the screw access hole and take out the bottom cotton ball.The cotton ball and the central screw were placed in a 95% ethanol solution for 24 hours to completely dissolve the infiltrated0.5% basic fuchsin solution,and the absorbance of the extract was analyzed by aluminometer,and the measurement was repeated three times,and the average value was taken.Statistical analysis of the absorbance values of the solutions was performed using SPSS 21.0 software to determine whether the differences were statistically significant.Results:(1)(1)The degree of dyeing of cotton balls in the screw hole gradually becomes shallower from top to bottom.(2)In the Z350 general-purpose and flow-type resin filling group,the absorbance of the two resin filling groups gradually decreased with the increase of the filling thickness(P<0.05).Among them,the absorbance was the highest in the group with a filling thickness of 1 mm,the second at 2 mm,and the lowest at 3 mm,with significant statistical difference(P<0.05);the filling thickness of Ceramage polymerized ceramicis 1mm.The absorbance was the highest in the groups,and there was no significant difference between the 2mm and 3mm groups(P>0.05).(3)The absorbance between the different resin groups of the same filling thickness was statistically different(P<0.05).In the groups with filling thickness of 1 and 2 mm,the absorbance of the Z350 flow type resin filling group was the highest,the Z350general-purpose resin was the second,and the Ceramage polymerized resin was the lowest,with statistically significant difference(P<0.05).There was no significant difference in absorbance between the three resin filling groups in the 3 mm group(P>0.05).Conclusion:(1)Under the experimental conditions,Ceramage polymerized ceramic resin has the lowest degree of microleakage,followed by Z350 general-purpose resin,and Z350 flowable resin has the most serious microleakage.(2)When the composite resin of the same material is filled with screw-fixed implant denture prosthesis screw access hole,the sealing effect will gradually improve with the increase of filling thickness,the order is: 3mm<2mm<1mm.(3)When the filling thickness reaches 3 mm,the edge sealing ability of the same composite resin is not significantly different from 2mm. |
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